To form an image on a sheet without skew, an image forming apparatus that forms an image on a sheet includes a skew correcting device for correcting skew of a sheet conveyed to an image forming unit.
For example, there is a skew correcting device that typically includes registration rollers or shutters on a conveying path between a sheet feeder for feeding a sheet and an image forming unit, the rollers or shutters being disposed upstream of the image forming unit. In this configuration, a roller pair (hereinafter referred to as an upstream roller pair) disposed upstream of the rollers or shutters nips and conveys a sheet fed from the sheet feeder. Then, the upstream roller pair brings the leading edge of the sheet into contact with a contact portion of the rollers or shutters to correct skew of the leading edge of the sheet (see Patent Literature (PTL) 1).
In this configuration, the upstream roller pair nips and conveys the sheet, and brings the leading edge of the sheet into contact with the nip of the registration roller pair to form a loop in the sheet. Thus, the leading edge of the sheet is aligned with the nip, so that skew of the sheet is corrected.